Studys on the Oxygen Containing Groups in the Artificial Coalification Products of the Low Rank Coals i Hokkaido

The present report concerns with the contents of the oxygen containing groups in the artificial coalification products (C‰, 60-80) of the low rank coals in Hokkaido (Tokachi lignite, Tsuchiya lignite and Tenpoku coal) and the results of estimation were compared with those of natural coals in order to make clear the artificial coalification mechanism.Acetylation method modified by Takeya and co-workers was used for the measurement of hydroxyl group.The carbonyl-carboxyl-and methoxyl groups were measured by oxidation method, ion exchange method with barium acetate and Zeisel's method respectively.The distribution of the oxygen containing groups in the artificial coalification products of the low rank coals was generally similar to that of natural coals. The contents of the oxygen containing groups (-OH-CO, -COOH, -OCH3 and C-O-C) in coalfication the artificial coalification products decrease with increase of their carbon content. The distribution of the oxygen containing groups of the artificial products of Tokachi lignite bus the same tendency with that of natural coals. It may be concluded that the contents of the oxygen containing groups in the artificial coalification products decrease with the increase of the time and temperature of artificial coalfication from the view points of the artificial coalification temperature-the atomic ratio, O' (oxygen containing group) /C' diagram, the artificial coalification time-the atomic ratio, and O' (oxygen containing group) /C'diagram.